Mental Imagery and Targeted Memory Reactivation in Insomnia

Condition(s) studied

Investigational drug(s) / intervention(s)

Imagery Rescripting (IR): Imagery rescripting (IR) is a technique where the individual is instructed to imagine a negative memory or image as vividly as possible, and to change it in a direction that he/she desires. IR seems particularly efficient because it is based on the experienced emotions during perceptual information processing, thereby eliciting stronger emotional responses than verbal processing.

Imagery Rescripting (IR) and Targeted Memory Reactivation (TMR) during sleep: Targeted Memory Reactivation (TMR) is a technique used to strengthen a memory trace during sleep. TMR is used to modify memory formation through the application of cues during sleep. In this TMR protocol, an olfactory cue is associated with the imagery rescripting (IR) during the day, and then administered during sleep. In that way, the replay of the associated memory and its corresponding neural representation in memory networks are artificially promoted, a procedure which usually strengthens memory consolidation. Previous studies have shown that TMR in sleep reduces emotional arousal, making it a promising technique for insomnia.

Sleep Hygiene: Sleep hygiene education includes modifications in the behavior (e.g., exercise, coffee, alcohol intake) and environment (e.g., light, noise, temperature conditions) that offer to the individual the foundation for healthy sleep. Sleep hygiene is an important component in treating ID, but insufficient and less effective than CBT-I when offered alone.

Sleep Hygiene + Odor: Sleep hygiene instructions will be applied in the presence of an odor, which will be also used during the night.

"Rocking bed" if patients still have insomnia complaints (ISI >10) after the 4 weeks of the intervention: Rocking stimulation boosts brain oscillations in deep sleep (i.e., sleep spindles and slow oscillations) into a rhythmic appearance supporting a neurophysiological mechanism whereby continuous rocking entrains endogenous thalamo-cortical sleep oscillations. The beneficial effects of rocking strengthening the continuity of sleep might have clinical applications and it will be of interest to evaluate if such non-pharmacological could improve sleep and reduce such features of hyperarousal in ID patients.

Study summary

In this clinical trial, the investigators test whether mental Imagery Rescripting (IR), a technique where the individual is instructed to transform a negative memory or image into a positive one, and olfactory Targeted Memory Reactivation (TMR), a technique used to strengthen memories, can reduce hyperarousal and insomnia severity in patients with Insomnia Disorder (ID).

Patients with ID will be randomized into four groups: in the first group (SH group), patients will have 4 weekly sessions (1 session/week) of a minimal intervention for insomnia (sleep hygiene information) in the presence of an odorless diffuser, which will be also used during the night. In the second group (IR group), patients will use IR during wakefulness to induce a state of relaxation and positive emotionality. More specifically, during 4 weekly sessions of IR, patients will imagine a negative scenario related to their pre-sleep images or current concerns (e.g., social interactions, self-image, sleep problem, nightmares) and transform it into a positive script. They will then perform IR every day for 4 weeks at home in the presence of an odorless diffuser, which will be also used during the night. In the third group, patients will undergo the same 4 weekly IR sessions and an odor will be paired to the positive imagery and will be diffused during the night (TMR group). Patients from this group will also perform IR every day for 4 weeks at home. Finally, the fourth group (OA group) will receive 4 weekly sessions of sleep hygiene instructions in the presence of an odor, which will be also used during the night.

Clinical evaluation of insomnia severity before and after the intervention will take place using the Insomnia Severity Index (ISI, primary outcome measure).

At the end of these interventions, patients with persistent symptoms will benefit from an alternative experimental treatment ("rocking bed") in which they will be cradled for one night.

The investigators hypothesize that patients treated with IR will have significantly reduced insomnia severity compared to participants who received a minimal intervention. They also hypothesize that patients of the TMR group, will have more reduced ID severity compared to participants performing IR and with an odorless diffuser, therefore without an association (IR group). Finally, they hypothesize that one night of sleeping in a rocking bed will improve objective measures of sleep in ID compared to a stationary condition.

Eligibility

Primary outcome measure(s)

• Insomnia Severity Index (ISI) — Baseline, 5 Weeks and 3 Months
  Standardized questionnaire that measures ID severity, the score ranges from 0-28, zero indicating no symptom severity and 28 indicating the higher symptom severity.

Trial sites (1)

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